Evidence for a vascular contribution to diffusion FMRI at high b value.
Recent work has suggested that diffusion-weighted functional magnetic resonance imaging (FMRI) with strong diffusion weighting (high b value) detects neuronal swelling that is directly related to neuronal firing. This would constitute a much more direct measure of brain activity than current methods...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
2007
|
| _version_ | 1797076536936890368 |
|---|---|
| author | Miller, K Bulte, D Devlin, H Robson, M Wise, R Woolrich, M Jezzard, P Behrens, T |
| author_facet | Miller, K Bulte, D Devlin, H Robson, M Wise, R Woolrich, M Jezzard, P Behrens, T |
| author_sort | Miller, K |
| collection | OXFORD |
| description | Recent work has suggested that diffusion-weighted functional magnetic resonance imaging (FMRI) with strong diffusion weighting (high b value) detects neuronal swelling that is directly related to neuronal firing. This would constitute a much more direct measure of brain activity than current methods and represent a major advance in neuroimaging. However, it has not been firmly established that the observed signal changes do not reflect residual vascular effects, which are known to exist at low b value. This study measures the vascular component of diffusion FMRI directly by using hypercapnia, which induces blood flow changes in the absence of a change in neuronal firing. Hypercapnia elicits a similar diffusion FMRI response to a visual stimulus including a rise in percent signal change with increasing b value, which was reported for visual activation. Analysis of the response timing found no evidence for an early response at high b value, which has been reported as evidence for a nonhemodynamic response. These results suggest that a large component of the diffusion FMRI signal at high b value is vascular rather than neuronal. |
| first_indexed | 2024-03-07T00:05:07Z |
| format | Journal article |
| id | oxford-uuid:7749d567-983a-48b8-a861-f58a3ceb6039 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T00:05:07Z |
| publishDate | 2007 |
| record_format | dspace |
| spelling | oxford-uuid:7749d567-983a-48b8-a861-f58a3ceb60392022-03-26T20:22:54ZEvidence for a vascular contribution to diffusion FMRI at high b value.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:7749d567-983a-48b8-a861-f58a3ceb6039EnglishSymplectic Elements at Oxford2007Miller, KBulte, DDevlin, HRobson, MWise, RWoolrich, MJezzard, PBehrens, TRecent work has suggested that diffusion-weighted functional magnetic resonance imaging (FMRI) with strong diffusion weighting (high b value) detects neuronal swelling that is directly related to neuronal firing. This would constitute a much more direct measure of brain activity than current methods and represent a major advance in neuroimaging. However, it has not been firmly established that the observed signal changes do not reflect residual vascular effects, which are known to exist at low b value. This study measures the vascular component of diffusion FMRI directly by using hypercapnia, which induces blood flow changes in the absence of a change in neuronal firing. Hypercapnia elicits a similar diffusion FMRI response to a visual stimulus including a rise in percent signal change with increasing b value, which was reported for visual activation. Analysis of the response timing found no evidence for an early response at high b value, which has been reported as evidence for a nonhemodynamic response. These results suggest that a large component of the diffusion FMRI signal at high b value is vascular rather than neuronal. |
| spellingShingle | Miller, K Bulte, D Devlin, H Robson, M Wise, R Woolrich, M Jezzard, P Behrens, T Evidence for a vascular contribution to diffusion FMRI at high b value. |
| title | Evidence for a vascular contribution to diffusion FMRI at high b value. |
| title_full | Evidence for a vascular contribution to diffusion FMRI at high b value. |
| title_fullStr | Evidence for a vascular contribution to diffusion FMRI at high b value. |
| title_full_unstemmed | Evidence for a vascular contribution to diffusion FMRI at high b value. |
| title_short | Evidence for a vascular contribution to diffusion FMRI at high b value. |
| title_sort | evidence for a vascular contribution to diffusion fmri at high b value |
| work_keys_str_mv | AT millerk evidenceforavascularcontributiontodiffusionfmriathighbvalue AT bulted evidenceforavascularcontributiontodiffusionfmriathighbvalue AT devlinh evidenceforavascularcontributiontodiffusionfmriathighbvalue AT robsonm evidenceforavascularcontributiontodiffusionfmriathighbvalue AT wiser evidenceforavascularcontributiontodiffusionfmriathighbvalue AT woolrichm evidenceforavascularcontributiontodiffusionfmriathighbvalue AT jezzardp evidenceforavascularcontributiontodiffusionfmriathighbvalue AT behrenst evidenceforavascularcontributiontodiffusionfmriathighbvalue |